1 files changed, 35 insertions, 23 deletions
diff --git a/contrib/llvm-project/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/contrib/llvm-project/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 7f5a7b666903..351fc3b0174f 100644
--- a/contrib/llvm-project/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/contrib/llvm-project/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2469,31 +2469,43 @@ Instruction *InstCombinerImpl::visitGetElementPtrInst(GetElementPtrInst &GEP) {
         DL.getIndexSizeInBits(AS)) {
       uint64_t TyAllocSize = DL.getTypeAllocSize(GEPEltType).getFixedValue();
 
-      bool Matched = false;
-      uint64_t C;
-      Value *V = nullptr;
       if (TyAllocSize == 1) {
-        V = GEP.getOperand(1);
-        Matched = true;
-      } else if (match(GEP.getOperand(1),
-                       m_AShr(m_Value(V), m_ConstantInt(C)))) {
-        if (TyAllocSize == 1ULL << C)
-          Matched = true;
-      } else if (match(GEP.getOperand(1),
-                       m_SDiv(m_Value(V), m_ConstantInt(C)))) {
-        if (TyAllocSize == C)
-          Matched = true;
+        // Canonicalize (gep i8* X, (ptrtoint Y)-(ptrtoint X)) to (bitcast Y),
+        // but only if the result pointer is only used as if it were an integer,
+        // or both point to the same underlying object (otherwise provenance is
+        // not necessarily retained).
+        Value *X = GEP.getPointerOperand();
+        Value *Y;
+        if (match(GEP.getOperand(1),
+                  m_Sub(m_PtrToInt(m_Value(Y)), m_PtrToInt(m_Specific(X)))) &&
+            GEPType == Y->getType()) {
+          bool HasSameUnderlyingObject =
+              getUnderlyingObject(X) == getUnderlyingObject(Y);
+          bool Changed = false;
+          GEP.replaceUsesWithIf(Y, [&](Use &U) {
+            bool ShouldReplace = HasSameUnderlyingObject ||
+                                 isa<ICmpInst>(U.getUser()) ||
+                                 isa<PtrToIntInst>(U.getUser());
+            Changed |= ShouldReplace;
+            return ShouldReplace;
+          });
+          return Changed ? &GEP : nullptr;
+        }
+      } else {
+        // Canonicalize (gep T* X, V / sizeof(T)) to (gep i8* X, V)
+        Value *V;
+        if ((has_single_bit(TyAllocSize) &&
+             match(GEP.getOperand(1),
+                   m_Exact(m_AShr(m_Value(V),
+                                  m_SpecificInt(countr_zero(TyAllocSize)))))) ||
+            match(GEP.getOperand(1),
+                  m_Exact(m_SDiv(m_Value(V), m_SpecificInt(TyAllocSize))))) {
+          GetElementPtrInst *NewGEP = GetElementPtrInst::Create(
+              Builder.getInt8Ty(), GEP.getPointerOperand(), V);
+          NewGEP->setIsInBounds(GEP.isInBounds());
+          return NewGEP;
+        }
       }
-
-      // Canonicalize (gep i8* X, (ptrtoint Y)-(ptrtoint X)) to (bitcast Y), but
-      // only if both point to the same underlying object (otherwise provenance
-      // is not necessarily retained).
-      Value *Y;
-      Value *X = GEP.getOperand(0);
-      if (Matched &&
-          match(V, m_Sub(m_PtrToInt(m_Value(Y)), m_PtrToInt(m_Specific(X)))) &&
-          getUnderlyingObject(X) == getUnderlyingObject(Y))
-        return CastInst::CreatePointerBitCastOrAddrSpaceCast(Y, GEPType);
     }
   }
   // We do not handle pointer-vector geps here.